Showing papers by "University of Turin published in 1975"

Changes in Plasma Growth Hormone Levels in Normal and Acromegalic Subjects Following Administration of 2-Bromo-α-Ergocryptine

Abstract: 2-Bromo-α-ergocryptine (CB-154), an ergot alkaloid that stimulates dopaminergic receptors, caused a widely varying, but significant increasein plasma GH levels in normal subject whereas a marked and protracted fall in values was observed in some patients with acromegaly. It is suggested that these effects were mediated by activation of either hypothalamic or hypophyseal dopaminergic receptors. The fact that GH values fell to or near normal levels in 4/8 cases suggests that CB-154 may have therapeutic possibilities in acromegaly.

I-region-associated determinants: expression on mitogen-stimulated lymphocytes and detection by cytotoxic T cells

Abstract: We have studied the expression of Ia-antigens, controlled by genes in the I-region of the H-2 complex, on phytohemagglutinin (PHA)-stimulated lymph node cells and on lipopolysaccharide (LPS)-stimulated spleen cells, and have compared these two types of cell populations as targets for killer cells in the cell mediated lympholysis (CML) assay. PHA targets are almost completely insensitive to complement-mediated lysis by anti-Ia sera while the majority of LPS targets are killed. T cell-mediated lysis against I-region determinants was also detected, and these determinants, in contrast to H-2K and H-2D CML determinants, seem to be much more strongly expressed on LPS-stimulated cells. No differences in the kinetics of the response to K- or I-region CML determinants were observed. Lysis by killer cells can also be obtained against incompatibilities which do not give rise to strong skin graft rejection and against determinants which are most probably controlled by genes outside the K-D interval.

Decreased Interferon Response by Lymphocytes from Children with Chronic Hepatitis

Abstract: Since a decreased interferon response has been linked with certain chronic viral infections, a preliminary study was undertaken to determine whether an altered interferon response may be involved in the pathogenesis of chronic hepatitis, a complication of type B hepatitis. The production of interferon by lymphocytes from patients with chronic hepatitis was compared with the production by lymphocytes from normal subjects. The amount of interferon produced by paramyxovirusstimulated lymphocytes from 16 patients was substantially smaller than that produced by lymphocytes from 12 healthy donors. The results indicate that decreased production of interferon may be responsible for the chronicity of the disease. However, further studies are necessary to establish causality.

Production of and some effects of ethylene in relation to Fusarium wilt of tomato

Abstract: The rate of evolution of ethylene from susceptible and resistant tomato plants, healthy or infected with Fusarium oxysporum f. sp. lycopersici was determined. In susceptible plants, the infection induced increases in ethylene production which reached a maximum from 9 to 10 days after inoculation, corresponding to the occurrence of marked foliar wilting and basal leaf abscission. Changes in ethylene production were not observed in infected resistant plants nor in plants inoculated with a form of F. oxysporum avirulent to the tomato. Marked increases in ethylene production were also found in uninfected plants during reversible physiological wilting and with mechanical or chemical injuries. The changes in ethylene production in infected susceptible plants were similar to the changes occuring in peroxidase and polyphenoloxidase activity in those plants. The activities of these enzymes in uninfected plants were strongly stimulated by exogenously supplied ethylene. Treatment of infected plants with ethylene aggravated the symptoms of disease.

Immunofluorescence detection of casein in human mammary dysplastic and neoplastic tissues.

Abstract: To detect and localize casein in human mammary dysplastic and neoplastic tissues, an indirect immunofluorescence method has been devised. Anti-casein antibodies have been obtained from rabbits immunized with casein isolated from human milk. Cryostat sections post-fixed in alcohol and paraffin sections from routinely formalin-fixed tissues proved suitable.

Structural identifiability of compartmental models and pathophysiological information from the kinetics of drugs

Abstract: The present paper shows how some basic concepts in system theory, such as controllability, observability and identifiability, can be very useful in the problem of the interpretation of the kinetic of drugs and in the processing experimental data. Particular attention is given to the structural identifiability analysis of the model of the kinetics of bromsulphalein (BSP), which has a complex hepatic metabolism (uptake, conjugation and excretion). The results of this analysis are then used to decide what information on the hepatobiliary functions can be derived from any practically feasible measurement technique.

Viral interference and interferon

Abstract: Viral interference is a phenomenon for which a cell infected by a virus becomes resistant toward a second outcoming infection by a superinfectant virus Even though other mechanisms are known, it can be assumed that most cases of viral interference occurring in natural conditions are mediated by interferon, a low molecular weight protein produced by the infected cell in response to a stimulus provided by viral nucleic acid(s) The interferon produced by a cell can migrate to other cells not yet involved by the spreading infection, transmitting to them the antiviral-resistant state Available evidence indicates that interferon acts by inducing the production of a second cellular protein, called antiviral protein, which is directly responsible for the antiviral state through some alterations of the cellular, virus-directed, proteosynthetic system In addition to the antiviral activity, the interferon system can affect the growth of several nonviral organisms and that of tumour cells; rather controversial effects have been shown also on the immune responses; the mechanisms underlying these effects are still nuclear However a relationship to the specific immune system is suggested also by the finding that interferon can be liberated by sensitized T-lymphocytes following antigenic stimulus Activation of the interferon system can be operated in vitro and in vivo also by several non-viral substances of various nature, such as nucleic acids, polysaccharides, aromatic amines, etc This fact, considering that interferon has been shown to play a critical role on the mechanisms of recovery from viral infections, may open new perspectives for their possible prophylactic and/or therapeutic use in viral diseases This problem can be approached also by administering exogenous interferon Encouraging preliminary results have so far been obtained either with interferon or its inducers However, several problems of various nature have to be resolved before considering the actual use of interferon system as a wide range antiviral drug in natural viral diseases of man

Climate and the weight/height relationship in sub-Saharan Africa.

Abstract: 25 populations of the rain forest and 44 of the open country, all descended from the West-Central African stock which lived in the latter biome, are compared for body weight and height. On a log weight/height diagram, the 69 populations cluster along a straight line which intersects the lines of equal body weight/surface ratio: the shorter the body size, the lower the ratio tends to be. The rain forest populations are concentrated in the lower part of the bivariate distribution. The shortest one, the Mbuti Pygmies, has a very low ratio despite a relatively heavy weight. The shorter stature of the rain forest populations seems to be largely genetic in origin; it probably results from selective pressure exerted by the thermal stres in this hot and wet biome where sweating is of low thermolytic efficiency. The amount of reduction of adult stature depends for a large part on the number of generations spent in the forest by the population. Line A (in figure 1) is similar to a growth trend. The 69 populations differ genetically by the target that growth has to reach on a common log weight/height trend line. They achieve this differentiation through different speeds of growth.

Immunofluorescence, histochemical and ultrastructural studies for the detection of multiple endocrine polypeptide tumours of the pancreas.

Abstract: Four endocrine tumours of the pancreas associated respectively with the Zollinger-Ellison syndrome (1 case) and with hypoglycaemia (3 cases) have been investigated by means of immunofluorescence, employing anti-insulin, anti-glucagon and anti-gastrin sera, endocrine cell stains and electron microscopy.

Role of precursor 16S RNA in assembly of E. coli 30S ribosomes.

Abstract: RECONSTITUTION of bacterial ribosomes occurs in vitro in a system containing ribosomal components only1, which suggests that ribosomes also form by self-assembly in vivo. This inference is reinforced by the fact that intermediary particles, containing a similar fraction of ribosomal proteins, are observed both in vitro and in vivo1–3. The in vitro reconstitution process, however, requires a very high energy of activation, presumably to force the intermediates into a rare conformational state1,4. This requirement is too high to be compatible with the rate of ribosome formation in vivo5. Furthermore, there is evidence that the rate-limiting step which leads to the accumulation of the precursor particles in vivo does not involve spontaneous conformational change of these particles6. Although all the information, therefore, required to construct a ribosome must be present in its components, it seems that cells use an additional mechanism to facilitate their assembly.

λ-Terms as total or partial functions on normal forms

Abstract: In this paper the set of λ -terras is split into 2ω+1 disjoint classes Ph (−ω≤h≤ω). This classification takes into account the meaning of a λ-term F as function on normal forms, and more precisely: 1 iff when auccessively applied to any number of normal forms it gives a λ-term without normal form 2 (0ω) iff when successively applied to h arbitrary normal forms it gives a λ-term which possesses normal form, but there exist h+1 normal forms X1,...,Xh+1 such that FX1...Xh+1 possesses no normal form 4 iff when successively applied to any number of normal forms it gives a λ-term which possesses normal form.

Stimulation of rat liver beta-galactosidase activity by ions.

Abstract: 1. The p -nitrophenyl β-D-galactosidase asctivity in rat liver homogenates of lysosome-rich fractions was shown to be markedly affected by the ionic composition of the medium. A stimulation of the reaction rate at pH 5 was produced by most of the salts tested, which contained anions such as acetate, SO 4 2− and Cl − , and cations such as Na + , K + and Mg 2+ . The most pronounced effect was observed with MgCl 2 . Only potassium glutamate was inhibitory. 2. Five peaks of β-galactosidase activity obtained by DEAE-cellulose chromatography were equally sensitive to changes in the ionic composition of the medium. In the presence of added NaC1, the whole rate-pH curve was displaced towards higher pH values, the optimum being shifted from 2.0-2.5 to 3.5. The stimulation at pH 5.0 appeared to be mainly due to changes in V max ., whereas the apparent K m was slightly modified. 3. Unlike the total, the free β-galactosidase activity remained unchanged or even declined when KC1 was added to the reaction medium.

Evidence for a membrane carrier molecule common to embryonal and tumour-specific antigenic determinants expressed by a mouse transplantable tumour.

Abstract: Rabbits were primed with membrane antigens solubilized from BALB/c embryo cells. After boosting with membrane antigens solubilized from a syngeneic transplantable adenocarcinoma, they developed a 'secondary' response against tumour-specific antigenic determinants. The antibodies against these determinants neither reacted with nor were absorbed by the antigens prepared from embryonal cells. However, the antigen displaying the tumour-specific determinants was bound by a reversed immunoadsorbent of insoluble anti-embryo antibodies. Indirect immunofluorescence experiments performed on adenocarcinoma cells in culture showed that, under conditions where redistribution of cell membrane components was induced, the anti-embryo antiserum aggregated the tumour-specific determinants. The purification of embryo and tumour-specific antigens achieved by affinity chromatography on insoluble antibody columns yielded three polypeptides of molecular weight close to 25,000, 20,000, and 10,000 Daltons respectively. It is suggested that the antigenic determinants responsible for tumour and embryo specificities in adenocarcinoma were located on the same molecule, or, more likely, on molecules which are closely associated in the plasma membrane and that do not dissociated in bile salts.

Dynamic properties of axonal transport of proteins and glycoproteins: A study based on the effects of metaphase blocking drugs in the developing optic pathway of chick embryos

Abstract: Some properties of the axonal transport of proteins and glycoproteins along the optic pathway of chick embryos and newly hatched chicks were studied by labelling retinal ganglion cells with 3H-proline or 3H-fucose. A study of the effects of colchicine (COL) and vinblastine (VLB) on embryonic axonal transport was also carried out. Marked changes in the efficiency of axonal transport were found throughout development. In particular, the fraction of retinal ganglion cell proteins which is rapidly exported toward tectal terminals increases during embryonic life but steadily decreases after hatching. Glycoprotein transport behaves similarly except that its efficiency is relatively higher at stages when critical events of synaptic maturation in the tectum are reported to occur. Embryonic axonal transport is blocked by COL and VLB at very low intravitreal concentrations. Retinal protein synthesis and the morphology of ganglion cells are profoundly altered by the drugs: in general, COL and VLB effects were much more marked in embryonic than in mature neurons. An analysis of the time course of rapid transport along embryonic optic axons was carried out by reducing the efflux of labelled proteins from the eye by giving VLB intravitreally 2 h after the pulse. It revealed some peculiar features in the retino-tectal migration of glycoproteins and confirmed their progressive accumulation within terminals as previously described by radioautography. These results suggest that axonal transport of proteins during embryonic life undergoes changes in parallel with synaptic maturation. It may thus be considered as one of the factors controlling the genesis of neuronal networks.